Is the waiting period (iddah) obligatory for the wife after a divorce decree is issued by the court if she had been separated from her husband for the previous three years?

If a woman is certain that her husband has divorced her with three pronouncements, then she has been irrevocably divorced from him (bainunah kubra), and she is not lawful for him again unless she marries another man willingly, he consummates the marriage with her, and then he divorces her or dies, and her waiting period ends. Her waiting period begins from the date of the divorce and ends after the completion of three menstrual cycles. If the husband denies the divorce and she cannot prove it before a judge, then it is not permissible for her to remain with him, and she must seek khul' (divorce at the wife's initiative). She should not marry anyone else until she obtains a divorce or khul' document.